Ronald S. Petralia and Ya-Xian Wang have run the Advanced Imaging Core facility of NIDCD since October 2011. This core is dedicated primarily to collaborating with and training other scientists in NIDCD in studies utilizing transmission electron microscopy (TEM). And we present an annual workshop on TEM as part of the EARssentials program. Some work also is done with other NIH institutes. In addition, Ronald Petralia regularly reviews papers for professional journals and reviews many various documents for NIDCD PIs, reviews grants, writes review papers and letters of recommendation, serves on several NIH committees and helps coordinate lab+office safety for NIDCD (including annual inspections and reports), and performs animal facility inspections as part of his duties in the ACUC. Recently, we have been preparing for the addition of a second electron microscope that will be dedicated largely to cryo-EM; it should be installed by early FY19. NIDCD: Lisa Cunningham lab: We looked at effects of heat shock on the release/uptake of exosomes in the utricle, in collaboration with the postBac IRTA fellow, Nora Welsh, and Andrew Breglio from the lab (manuscript in preparation). Katie Kindt lab: The Core continues periodically to use TEM to study the hair cells and associated supporting cells of the zebrafish neuromasts and utricle. In 2017 and 2018, we published papers on neuromasts in J. Neurosci. and Nat. Comm. (refs. 1,2), and we have another in preparation. Tom Friedman/Inna Belyantseva lab: We have 2 collaborations: both will be submitted soon; in one, we provided detailed 3D analyses of stereocilia and rootlets associated with TRIOBP mutants; and in the other, we performed immunogold localization of TBC1D24 (Risa Tona). The Core continues to advise Inna Belyantseva on TEM techniques including tomography, to optimize ultrastructural studies of hair cells and stereocilia. We also assist Inna with tissue preparation, e.g., freeze substitution. Others: We have some research with Doris Wu and Kazuya Ono that may continue. We also provide some assistance to the lab of Bechara Kachar, including review of manuscripts, and help for Willy Sun and Evan Krystofiak related to TEM and SEM. We have discussed a possible future project with Mike Hoa. Other NIH institutes: NINDS: We published a study in 2017 in Neuron, with Wei Lu/Wenyan Han/Jun Li, on two synaptic cell adhesion molecules associated with GABAergic synapse development in the hippocampus (ref. 3). We have another study almost completed, and also are working on a possible third study. Also, we recently completed a study with Katherine Roche/Richa Lomash on neurolastin function, looking at structural changes in neurons in the brain of the mutant (manuscript is near submission). NICHD: In 2018, we published a paper with Dax Hoffman/Lin Lin on a potassium channel auxiliary protein (ref. 4), and we are working on a new project in this area. We also have studies with 2 more labs in NICHD, both on zebrafish neuromast development, with Katie Drerup/Dane Kawano, and with Ajay Chitnis/Damian Dalle Nogare. We also performed some preliminary studies for Andres Buonanno, and may resume studies in the near future; and we have discussed a possible future project with Juan Bonifacino. NIA: We published research papers with Mark Mattson/Pamela Yao on sonic hedgehog and on neuronal purine enzymes, and review papers on invaginating presynaptic terminals (refs. 5-8). We continue to work on various studies of neuronal function. NIMH: We are working with Zheng Li/Kaizheng Duan on 2 studies of mitophagy in the amygdala and hippocampus associated with social anxiety. NEI: We agreed to perform TEM studies on zebrafish retina, as part of a new K99 proposal for Wei Li/Juan Angueyra-Aristizabal; this also is a collaboration with Katie Kindt of NIDCD. Others: At some point, we may return to previous studies with Nahid Tayebi/Ellen Sidransky (NHGRI), and with Gail Seabold (formerly NIDCD/currently OITE)/Florentina Soto (Wash. Univ. School of Medicine). Outside NIH: Recently, we have been reducing our participation in collaborations outside of NIH due to time restrictions; we plan to phase them out mostly by 2019. Gavin Rumbaugh/Massimiliano Aceti (Scripps Institute): we had submitted a paper on function of Syngap1 last year, but we dont know its status. Also, we may continue studies with Martin Horak (Head-Dept. Neurochem., Inst. Exp. Med., Czech Rep.). In addition to collaborations, Ron Petralia has served as a consultant on studies of T. Fujikawa (Japan)-GluRs in hair cell synapses.